diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 0400f1bc8372..4cc507275f16 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2011-12-09  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gimple-fold.c (gimple_fold_stmt_to_constant_1) <GIMPLE_UNARY_RHS>:
+	Also check the TYPE_MODE to recognize useless pointer conversions.
+
 2011-12-09  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/51117
diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
index 5da9be37575f..91dd8fc58924 100644
--- a/gcc/gimple-fold.c
+++ b/gcc/gimple-fold.c
@@ -2517,8 +2517,10 @@ gimple_fold_stmt_to_constant_1 (gimple stmt, tree (*valueize) (tree))
 	      if (CONVERT_EXPR_CODE_P (subcode)
 		  && POINTER_TYPE_P (TREE_TYPE (lhs))
 		  && POINTER_TYPE_P (TREE_TYPE (op0))
-		  && (TYPE_ADDR_SPACE (TREE_TYPE (lhs))
-		      == TYPE_ADDR_SPACE (TREE_TYPE (op0))))
+		  && TYPE_ADDR_SPACE (TREE_TYPE (lhs))
+		     == TYPE_ADDR_SPACE (TREE_TYPE (op0))
+		  && TYPE_MODE (TREE_TYPE (lhs))
+		     == TYPE_MODE (TREE_TYPE (op0)))
 		return op0;
 
               return
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 5c3e51baa99f..ac300e869f17 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2011-12-09  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gcc.c-torture/compile/20111209-1.c: New test.
+
 2011-12-09  Jason Merrill  <jason@redhat.com>
 
 	PR c++/51151
diff --git a/gcc/testsuite/gcc.c-torture/compile/20111209-1.c b/gcc/testsuite/gcc.c-torture/compile/20111209-1.c
new file mode 100644
index 000000000000..c7f832a9e372
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/20111209-1.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target s390x-*-* *-*-*vms* } } */
+
+typedef char* char_ptr32 __attribute__ ((mode(SI)));
+
+char_ptr32 getenv (const char *name);
+unsigned long strlen (const char *str);
+
+void
+__gnat_getenv (char *name, int *len, char **value)
+{
+  *value = getenv (name);
+  *len = strlen (*value);
+}